Baby Sam's rash is mimicking measles

With the contagious culprit ruled out, what was the real cause of this infant’s rash?
maculopapular-rash

Sam, aged 12 months, was brought into the ED by his parents with a two-day history of rash, associated with a five-day history of fever, coryzal symptoms and decreased food intake.

There was no associated cough. Two days before the onset of the fever, Sam had received his 12-month MMR, haemophilus influenzae type b and meningococcal C vaccinations.1